hwmon: New driver for the SMSC EMC6W201

This is a new driver for the SMSC EMC6W201 hardware monitoring device.
The device is functionally close to the EMC6D100 series, but is
register-incompatible.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Harry G McGavran Jr <w5pny@arrl.net>
Tested-by: Jeff Rickman <jrickman@myamigos.us>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

4 files changed, 592 insertions, 0 deletions

diff --git a/Documentation/hwmon/emc6w201 b/Documentation/hwmon/emc6w201
new file mode 100644
index 000000000000..32f355aaf56b
--- /dev/null
+++ b/Documentation/hwmon/emc6w201
@@ -0,0 +1,42 @@
+Kernel driver emc6w201
+======================
+
+Supported chips:
+  * SMSC EMC6W201
+    Prefix: 'emc6w201'
+    Addresses scanned: I2C 0x2c, 0x2d, 0x2e
+    Datasheet: Not public
+
+Author: Jean Delvare <khali@linux-fr.org>
+
+
+Description
+-----------
+
+From the datasheet:
+
+"The EMC6W201 is an environmental monitoring device with automatic fan
+control capability and enhanced system acoustics for noise suppression.
+This ACPI compliant device provides hardware monitoring for up to six
+voltages (including its own VCC) and five external thermal sensors,
+measures the speed of up to five fans, and controls the speed of
+multiple DC fans using three Pulse Width Modulator (PWM) outputs. Note
+that it is possible to control more than three fans by connecting two
+fans to one PWM output. The EMC6W201 will be available in a 36-pin
+QFN package."
+
+The device is functionally close to the EMC6D100 series, but is
+register-incompatible.
+
+The driver currently only supports the monitoring of the voltages,
+temperatures and fan speeds. Limits can be changed. Alarms are not
+supported, and neither is fan speed control.
+
+
+Known Systems With EMC6W201
+---------------------------
+
+The EMC6W201 is a rare device, only found on a few systems, made in
+2005 and 2006. Known systems with this device:
+* Dell Precision 670 workstation
+* Gigabyte 2CEWH mainboard
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 900409615ae9..16db83c83c8b 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -988,6 +988,16 @@ config SENSORS_EMC2103
 	  This driver can also be built as a module.  If so, the module
 	  will be called emc2103.
 
+config SENSORS_EMC6W201
+	tristate "SMSC EMC6W201"
+	depends on I2C
+	help
+	  If you say yes here you get support for the SMSC EMC6W201
+	  hardware monitoring chip.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called emc6w201.
+
 config SENSORS_SMSC47M1
 	tristate "SMSC LPC47M10x and compatibles"
 	help
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 8a57eca7a764..28061cfa0cdb 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -46,6 +46,7 @@ obj-$(CONFIG_SENSORS_DS620)	+= ds620.o
 obj-$(CONFIG_SENSORS_DS1621)	+= ds1621.o
 obj-$(CONFIG_SENSORS_EMC1403)	+= emc1403.o
 obj-$(CONFIG_SENSORS_EMC2103)	+= emc2103.o
+obj-$(CONFIG_SENSORS_EMC6W201)	+= emc6w201.o
 obj-$(CONFIG_SENSORS_F71805F)	+= f71805f.o
 obj-$(CONFIG_SENSORS_F71882FG)	+= f71882fg.o
 obj-$(CONFIG_SENSORS_F75375S)	+= f75375s.o
diff --git a/drivers/hwmon/emc6w201.c b/drivers/hwmon/emc6w201.c
new file mode 100644
index 000000000000..e0ef32378ac6
--- /dev/null
+++ b/drivers/hwmon/emc6w201.c
@@ -0,0 +1,539 @@
+/*
+ * emc6w201.c - Hardware monitoring driver for the SMSC EMC6W201
+ * Copyright (C) 2011  Jean Delvare <khali@linux-fr.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/jiffies.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/err.h>
+#include <linux/mutex.h>
+
+/*
+ * Addresses to scan
+ */
+
+static const unsigned short normal_i2c[] = { 0x2c, 0x2d, 0x2e, I2C_CLIENT_END };
+
+/*
+ * The EMC6W201 registers
+ */
+
+#define EMC6W201_REG_IN(nr)		(0x20 + (nr))
+#define EMC6W201_REG_TEMP(nr)		(0x26 + (nr))
+#define EMC6W201_REG_FAN(nr)		(0x2C + (nr) * 2)
+#define EMC6W201_REG_COMPANY		0x3E
+#define EMC6W201_REG_VERSTEP		0x3F
+#define EMC6W201_REG_CONFIG		0x40
+#define EMC6W201_REG_IN_LOW(nr)		(0x4A + (nr) * 2)
+#define EMC6W201_REG_IN_HIGH(nr)	(0x4B + (nr) * 2)
+#define EMC6W201_REG_TEMP_LOW(nr)	(0x56 + (nr) * 2)
+#define EMC6W201_REG_TEMP_HIGH(nr)	(0x57 + (nr) * 2)
+#define EMC6W201_REG_FAN_MIN(nr)	(0x62 + (nr) * 2)
+
+enum { input, min, max } subfeature;
+
+/*
+ * Per-device data
+ */
+
+struct emc6w201_data {
+	struct device *hwmon_dev;
+	struct mutex update_lock;
+	char valid; /* zero until following fields are valid */
+	unsigned long last_updated; /* in jiffies */
+
+	/* registers values */
+	u8 in[3][6];
+	s8 temp[3][6];
+	u16 fan[2][5];
+};
+
+/*
+ * Combine LSB and MSB registers in a single value
+ * Locking: must be called with data->update_lock held
+ */
+static u16 emc6w201_read16(struct i2c_client *client, u8 reg)
+{
+	int lsb, msb;
+
+	lsb = i2c_smbus_read_byte_data(client, reg);
+	msb = i2c_smbus_read_byte_data(client, reg + 1);
+	if (lsb < 0 || msb < 0) {
+		dev_err(&client->dev, "16-bit read failed at 0x%02x\n", reg);
+		return 0xFFFF;	/* Arbitrary value */
+	}
+
+	return (msb << 8) | lsb;
+}
+
+/*
+ * Write 16-bit value to LSB and MSB registers
+ * Locking: must be called with data->update_lock held
+ */
+static int emc6w201_write16(struct i2c_client *client, u8 reg, u16 val)
+{
+	int err;
+
+	err = i2c_smbus_write_byte_data(client, reg, val & 0xff);
+	if (!err)
+		err = i2c_smbus_write_byte_data(client, reg + 1, val >> 8);
+	if (err < 0)
+		dev_err(&client->dev, "16-bit write failed at 0x%02x\n", reg);
+
+	return err;
+}
+
+static struct emc6w201_data *emc6w201_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct emc6w201_data *data = i2c_get_clientdata(client);
+	int nr;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+		for (nr = 0; nr < 6; nr++) {
+			data->in[input][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_IN(nr));
+			data->in[min][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_IN_LOW(nr));
+			data->in[max][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_IN_HIGH(nr));
+		}
+
+		for (nr = 0; nr < 6; nr++) {
+			data->temp[input][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_TEMP(nr));
+			data->temp[min][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_TEMP_LOW(nr));
+			data->temp[max][nr] =
+				i2c_smbus_read_byte_data(client,
+						EMC6W201_REG_TEMP_HIGH(nr));
+		}
+
+		for (nr = 0; nr < 5; nr++) {
+			data->fan[input][nr] =
+				emc6w201_read16(client,
+						EMC6W201_REG_FAN(nr));
+			data->fan[min][nr] =
+				emc6w201_read16(client,
+						EMC6W201_REG_FAN_MIN(nr));
+		}
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+/*
+ * Sysfs callback functions
+ */
+
+static const u16 nominal_mv[6] = { 2500, 1500, 3300, 5000, 1500, 1500 };
+
+static ssize_t show_in(struct device *dev, struct device_attribute *devattr,
+	char *buf)
+{
+	struct emc6w201_data *data = emc6w201_update_device(dev);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+
+	return sprintf(buf, "%u\n",
+		       (unsigned)data->in[sf][nr] * nominal_mv[nr] / 0xC0);
+}
+
+static ssize_t set_in(struct device *dev, struct device_attribute *devattr,
+		      const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct emc6w201_data *data = i2c_get_clientdata(client);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+	int err;
+	long val;
+	u8 reg;
+
+	err = strict_strtol(buf, 10, &val);
+	if (err < 0)
+		return err;
+
+	val = DIV_ROUND_CLOSEST(val * 0xC0, nominal_mv[nr]);
+	reg = (sf == min) ? EMC6W201_REG_IN_LOW(nr)
+			  : EMC6W201_REG_IN_HIGH(nr);
+
+	mutex_lock(&data->update_lock);
+	data->in[sf][nr] = SENSORS_LIMIT(val, 0, 255);
+	err = i2c_smbus_write_byte_data(client, reg, data->in[sf][nr]);
+	mutex_unlock(&data->update_lock);
+
+	return err < 0 ? err : count;
+}
+
+static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
+	char *buf)
+{
+	struct emc6w201_data *data = emc6w201_update_device(dev);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+
+	return sprintf(buf, "%d\n", (int)data->temp[sf][nr] * 1000);
+}
+
+static ssize_t set_temp(struct device *dev, struct device_attribute *devattr,
+			const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct emc6w201_data *data = i2c_get_clientdata(client);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+	int err;
+	long val;
+	u8 reg;
+
+	err = strict_strtol(buf, 10, &val);
+	if (err < 0)
+		return err;
+
+	val /= 1000;
+	reg = (sf == min) ? EMC6W201_REG_TEMP_LOW(nr)
+			  : EMC6W201_REG_TEMP_HIGH(nr);
+
+	mutex_lock(&data->update_lock);
+	data->temp[sf][nr] = SENSORS_LIMIT(val, -127, 128);
+	err = i2c_smbus_write_byte_data(client, reg, data->temp[sf][nr]);
+	mutex_unlock(&data->update_lock);
+
+	return err < 0 ? err : count;
+}
+
+static ssize_t show_fan(struct device *dev, struct device_attribute *devattr,
+	char *buf)
+{
+	struct emc6w201_data *data = emc6w201_update_device(dev);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+	unsigned rpm;
+
+	if (data->fan[sf][nr] == 0 || data->fan[sf][nr] == 0xFFFF)
+		rpm = 0;
+	else
+		rpm = 5400000U / data->fan[sf][nr];
+
+	return sprintf(buf, "%u\n", rpm);
+}
+
+static ssize_t set_fan(struct device *dev, struct device_attribute *devattr,
+		       const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct emc6w201_data *data = i2c_get_clientdata(client);
+	int sf = to_sensor_dev_attr_2(devattr)->index;
+	int nr = to_sensor_dev_attr_2(devattr)->nr;
+	int err;
+	unsigned long val;
+
+	err = strict_strtoul(buf, 10, &val);
+	if (err < 0)
+		return err;
+
+	if (val == 0) {
+		val = 0xFFFF;
+	} else {
+		val = DIV_ROUND_CLOSEST(5400000U, val);
+		val = SENSORS_LIMIT(val, 0, 0xFFFE);
+	}
+
+	mutex_lock(&data->update_lock);
+	data->fan[sf][nr] = val;
+	err = emc6w201_write16(client, EMC6W201_REG_FAN_MIN(nr),
+			       data->fan[sf][nr]);
+	mutex_unlock(&data->update_lock);
+
+	return err < 0 ? err : count;
+}
+
+static SENSOR_DEVICE_ATTR_2(in0_input, S_IRUGO, show_in, NULL, 0, input);
+static SENSOR_DEVICE_ATTR_2(in0_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    0, min);
+static SENSOR_DEVICE_ATTR_2(in0_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    0, max);
+static SENSOR_DEVICE_ATTR_2(in1_input, S_IRUGO, show_in, NULL, 1, input);
+static SENSOR_DEVICE_ATTR_2(in1_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    1, min);
+static SENSOR_DEVICE_ATTR_2(in1_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    1, max);
+static SENSOR_DEVICE_ATTR_2(in2_input, S_IRUGO, show_in, NULL, 2, input);
+static SENSOR_DEVICE_ATTR_2(in2_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    2, min);
+static SENSOR_DEVICE_ATTR_2(in2_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    2, max);
+static SENSOR_DEVICE_ATTR_2(in3_input, S_IRUGO, show_in, NULL, 3, input);
+static SENSOR_DEVICE_ATTR_2(in3_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    3, min);
+static SENSOR_DEVICE_ATTR_2(in3_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    3, max);
+static SENSOR_DEVICE_ATTR_2(in4_input, S_IRUGO, show_in, NULL, 4, input);
+static SENSOR_DEVICE_ATTR_2(in4_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    4, min);
+static SENSOR_DEVICE_ATTR_2(in4_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    4, max);
+static SENSOR_DEVICE_ATTR_2(in5_input, S_IRUGO, show_in, NULL, 5, input);
+static SENSOR_DEVICE_ATTR_2(in5_min, S_IRUGO | S_IWUSR, show_in, set_in,
+			    5, min);
+static SENSOR_DEVICE_ATTR_2(in5_max, S_IRUGO | S_IWUSR, show_in, set_in,
+			    5, max);
+
+static SENSOR_DEVICE_ATTR_2(temp1_input, S_IRUGO, show_temp, NULL, 0, input);
+static SENSOR_DEVICE_ATTR_2(temp1_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    0, min);
+static SENSOR_DEVICE_ATTR_2(temp1_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    0, max);
+static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp, NULL, 1, input);
+static SENSOR_DEVICE_ATTR_2(temp2_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    1, min);
+static SENSOR_DEVICE_ATTR_2(temp2_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    1, max);
+static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp, NULL, 2, input);
+static SENSOR_DEVICE_ATTR_2(temp3_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    2, min);
+static SENSOR_DEVICE_ATTR_2(temp3_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    2, max);
+static SENSOR_DEVICE_ATTR_2(temp4_input, S_IRUGO, show_temp, NULL, 3, input);
+static SENSOR_DEVICE_ATTR_2(temp4_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    3, min);
+static SENSOR_DEVICE_ATTR_2(temp4_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    3, max);
+static SENSOR_DEVICE_ATTR_2(temp5_input, S_IRUGO, show_temp, NULL, 4, input);
+static SENSOR_DEVICE_ATTR_2(temp5_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    4, min);
+static SENSOR_DEVICE_ATTR_2(temp5_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    4, max);
+static SENSOR_DEVICE_ATTR_2(temp6_input, S_IRUGO, show_temp, NULL, 5, input);
+static SENSOR_DEVICE_ATTR_2(temp6_min, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    5, min);
+static SENSOR_DEVICE_ATTR_2(temp6_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
+			    5, max);
+
+static SENSOR_DEVICE_ATTR_2(fan1_input, S_IRUGO, show_fan, NULL, 0, input);
+static SENSOR_DEVICE_ATTR_2(fan1_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
+			    0, min);
+static SENSOR_DEVICE_ATTR_2(fan2_input, S_IRUGO, show_fan, NULL, 1, input);
+static SENSOR_DEVICE_ATTR_2(fan2_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
+			    1, min);
+static SENSOR_DEVICE_ATTR_2(fan3_input, S_IRUGO, show_fan, NULL, 2, input);
+static SENSOR_DEVICE_ATTR_2(fan3_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
+			    2, min);
+static SENSOR_DEVICE_ATTR_2(fan4_input, S_IRUGO, show_fan, NULL, 3, input);
+static SENSOR_DEVICE_ATTR_2(fan4_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
+			    3, min);
+static SENSOR_DEVICE_ATTR_2(fan5_input, S_IRUGO, show_fan, NULL, 4, input);
+static SENSOR_DEVICE_ATTR_2(fan5_min, S_IRUGO | S_IWUSR, show_fan, set_fan,
+			    4, min);
+
+static struct attribute *emc6w201_attributes[] = {
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	&sensor_dev_attr_in0_min.dev_attr.attr,
+	&sensor_dev_attr_in0_max.dev_attr.attr,
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in1_min.dev_attr.attr,
+	&sensor_dev_attr_in1_max.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in2_min.dev_attr.attr,
+	&sensor_dev_attr_in2_max.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in3_min.dev_attr.attr,
+	&sensor_dev_attr_in3_max.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	&sensor_dev_attr_in4_min.dev_attr.attr,
+	&sensor_dev_attr_in4_max.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+	&sensor_dev_attr_in5_min.dev_attr.attr,
+	&sensor_dev_attr_in5_max.dev_attr.attr,
+
+	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_temp1_min.dev_attr.attr,
+	&sensor_dev_attr_temp1_max.dev_attr.attr,
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp2_min.dev_attr.attr,
+	&sensor_dev_attr_temp2_max.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_min.dev_attr.attr,
+	&sensor_dev_attr_temp3_max.dev_attr.attr,
+	&sensor_dev_attr_temp4_input.dev_attr.attr,
+	&sensor_dev_attr_temp4_min.dev_attr.attr,
+	&sensor_dev_attr_temp4_max.dev_attr.attr,
+	&sensor_dev_attr_temp5_input.dev_attr.attr,
+	&sensor_dev_attr_temp5_min.dev_attr.attr,
+	&sensor_dev_attr_temp5_max.dev_attr.attr,
+	&sensor_dev_attr_temp6_input.dev_attr.attr,
+	&sensor_dev_attr_temp6_min.dev_attr.attr,
+	&sensor_dev_attr_temp6_max.dev_attr.attr,
+
+	&sensor_dev_attr_fan1_input.dev_attr.attr,
+	&sensor_dev_attr_fan1_min.dev_attr.attr,
+	&sensor_dev_attr_fan2_input.dev_attr.attr,
+	&sensor_dev_attr_fan2_min.dev_attr.attr,
+	&sensor_dev_attr_fan3_input.dev_attr.attr,
+	&sensor_dev_attr_fan3_min.dev_attr.attr,
+	&sensor_dev_attr_fan4_input.dev_attr.attr,
+	&sensor_dev_attr_fan4_min.dev_attr.attr,
+	&sensor_dev_attr_fan5_input.dev_attr.attr,
+	&sensor_dev_attr_fan5_min.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group emc6w201_group = {
+	.attrs = emc6w201_attributes,
+};
+
+/*
+ * Driver interface
+ */
+
+/* Return 0 if detection is successful, -ENODEV otherwise */
+static int emc6w201_detect(struct i2c_client *client,
+			   struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+	int company, verstep, config;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
+		return -ENODEV;
+
+	/* Identification */
+	company = i2c_smbus_read_byte_data(client, EMC6W201_REG_COMPANY);
+	if (company != 0x5C)
+		return -ENODEV;
+	verstep = i2c_smbus_read_byte_data(client, EMC6W201_REG_VERSTEP);
+	if (verstep < 0 || (verstep & 0xF0) != 0xB0)
+		return -ENODEV;
+	if ((verstep & 0x0F) > 2) {
+		dev_dbg(&client->dev, "Unknwown EMC6W201 stepping %d\n",
+			verstep & 0x0F);
+		return -ENODEV;
+	}
+
+	/* Check configuration */
+	config = i2c_smbus_read_byte_data(client, EMC6W201_REG_CONFIG);
+	if ((config & 0xF4) != 0x04)
+		return -ENODEV;
+	if (!(config & 0x01)) {
+		dev_err(&client->dev, "Monitoring not enabled\n");
+		return -ENODEV;
+	}
+
+	strlcpy(info->type, "emc6w201", I2C_NAME_SIZE);
+
+	return 0;
+}
+
+static int emc6w201_probe(struct i2c_client *client,
+			  const struct i2c_device_id *id)
+{
+	struct emc6w201_data *data;
+	int err;
+
+	data = kzalloc(sizeof(struct emc6w201_data), GFP_KERNEL);
+	if (!data) {
+		err = -ENOMEM;
+		goto exit;
+	}
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* Create sysfs attribute */
+	err = sysfs_create_group(&client->dev.kobj, &emc6w201_group);
+	if (err)
+		goto exit_free;
+
+	/* Expose as a hwmon device */
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+	if (IS_ERR(data->hwmon_dev)) {
+		err = PTR_ERR(data->hwmon_dev);
+		goto exit_remove;
+	}
+
+	return 0;
+
+ exit_remove:
+	sysfs_remove_group(&client->dev.kobj, &emc6w201_group);
+ exit_free:
+	kfree(data);
+ exit:
+	return err;
+}
+
+static int emc6w201_remove(struct i2c_client *client)
+{
+	struct emc6w201_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &emc6w201_group);
+	kfree(data);
+
+	return 0;
+}
+
+static const struct i2c_device_id emc6w201_id[] = {
+	{ "emc6w201", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, emc6w201_id);
+
+static struct i2c_driver emc6w201_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "emc6w201",
+	},
+	.probe		= emc6w201_probe,
+	.remove		= emc6w201_remove,
+	.id_table	= emc6w201_id,
+	.detect		= emc6w201_detect,
+	.address_list	= normal_i2c,
+};
+
+static int __init sensors_emc6w201_init(void)
+{
+	return i2c_add_driver(&emc6w201_driver);
+}
+module_init(sensors_emc6w201_init);
+
+static void __exit sensors_emc6w201_exit(void)
+{
+	i2c_del_driver(&emc6w201_driver);
+}
+module_exit(sensors_emc6w201_exit);
+
+MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
+MODULE_DESCRIPTION("SMSC EMC6W201 hardware monitoring driver");
+MODULE_LICENSE("GPL");